Photoconductivity of textured γ-In 2Se 3− xTe x (0≤ x≤0.5) thin films

Abstract

Textured thin films of γ-In 2Se 3 and γ-In 2(Se,Te) 3 have been prepared by alternate thermal evaporation of In and (Se,Te) layers on glass substrates. The crystallization of the as-deposited films was performed by post-deposition heat treatment in neutral atmosphere. Photoconductivity measurements were performed on films of both compounds in order to study the effect of crystalline quality and Te on the photoconductive behaviour of the films. It has been shown for γ-In 2Se 3 that the photocurrent is higher in films with good texture and large grains than in the films with less better quality. Moreover, the photocurrent is found to be about two orders of magnitude higher in γ-In 2(Se,Te) 3 films with Te amount up to 10 at.%. On the other hand the variation of the photocurrent with incident photon energy allowed us to determine the energy gap E g of both compounds and to confirm the E g lowering by introducing Te.